Breast Cancer Flashcards
Endocrine Therapy
Treatment of choice used for pts with hormone receptor positive tumors who exhibit the first sign of metastatic dz in soft tissue, bone, or pleura
Goals of Endocrine Therapy
- Decrease circulating levels of estrogen
- Prevent effects of estrogen on breast cancer cell by blocking the hormone receptors or down regulating the presence of those receptors
Aromatase Inhibitors
- Anastrozole
- Letrozole
- Exemestane
MOA for aromatase inhibitors
- Prevent aromatase from converting androgens to estrone and estradiol
- Anastrozole/Letrozole are non-steroidal, they are reversibly competitive inhibitors of aromatase, 1st line tx
- Exemestane is steroidal and irreversible
Anti-estrogens
- SERMS
- Pure anti-estrogens
MOA of anti-estrogens
Bind to estrogen receptor, which inhibit receptor mediated gene transcription and therefore block the effect of estrogen on the end target
SERMs
- Tamoxifen
- Toremifene
- Raloxifene
MOA of SERMs
- Inhibit proliferation of cancer cells in the breast BUT stimulate proliferation of uterine endometrial cells. These do not damage the receptors, just block them
Pure Anti-estrogens
Fulvestrant
MOA of Pure Anti-estrogen
Bind to estrogen receptor, inhibit estrogen binding, and degrade the drug estrogen-receptor complex therefore decreasing the amount of ER on tumor cell surfaces. These damage the receptors
LHRH analogs
- Leuprolide
- Goserelin (used for metastatic breast cancer)
- Triptorelin
MOA of LHRH analogs
Downregulates LHRH receptors in the pituitary which results in decreased levels of LH. Once LH decreases, estrogen will also decrease to very minimal levels (simulates an oophorectomy, aka taking the ovaries out)
Use for premenopuasal women
LHRH analog Side Effects
- Hot flashes
When should you NOT use LHRH analogs?
In HER positive breast cancers. (You would use trastuzumab/ herceptin)
